Stereotactic radiation therapy (SRT) has greatly impacted veterinary radiation oncology, decreasing overall treatment time and permitting efficacious treatment of gross disease. SRT provides radiation alternatives for tumors in previously inaccessible locations. As with traditional fractionated radiation, the concept of uncomplicated tumor control should remain a fundamental principle of SRT. This principle is based on the concept that a certain percentage of patients may be more suspectable to clinically significant late effects. However, lessening the dose to minimize late effects may underdose the rest of the patient population, reducing tumor control and resulting in decreased overall survival. In addition to late radiation effects, SRT seems to have a more profound impact on gross disease that can lead to complications requiring management.

This talk will address prevention of radiation effects by proper adherence to important normal tissue constraints and guidelines for providing standardized contouring information. It will also address identification of important pretreatment, intra-treatment, and post-treatment factors that may adversely impact outcome as well as drugs used during and after treatment that may help mitigate radiation effects. Included will be guidance of how to determine when and what type of surgical management is needed when late radiation effects occur following SRT.

Some tumors, because of size and location, may not have surgical options, and tumor control following fractionated radiation may be historically poor. Adverse effects following SRT can occur when tumors that have already invaded and destroyed adjacent bone and other tissues. For these cases, consultation with a surgical oncologist is necessary prior to SRT.

SRT is an important tool in veterinary oncology. Radiation oncologists need to continually re-evaluate tumor control and radiation effects in their patients to improve therapeutic gain and optimize protocols. Surgical oncologists are important team members and should work with radiation oncologists to improve management of late effects.